The invention relates generally to a medical device, and more particularly to a medicament delivery device for automatically mixing a medicament and injecting the medicament into a body of a patient.
Exposure to certain substances, such as, for example, peanuts, shellfish, bee venom, certain drugs, toxins, and the like, can cause allergic reactions in some individuals. Such allergic reactions can, at times, lead to anaphylactic shock, which can cause a sharp drop in blood pressure, hives, and/or severe airway constriction. Accordingly, responding rapidly to mitigate the effects from such exposures can prevent injury and/or death. For example, in certain situations, an injection of epinephrine (i.e., adrenaline) can provide substantial and/or complete relief from the allergic reaction. In other situations, for example, an injection of an antidote to a toxin can greatly reduce and/or eliminate the harm potentially caused by the exposure. Similarly, an injection of glucagon can reduce and/or eliminate the harm potentially caused by reduced blood glucose levels in individuals who suffer from diabetes.
Because emergency medical facilities may not be available when an individual is suffering from a medical condition, some individuals carry an auto-injector to rapidly self-administer a medicament in response to such medical conditions. Some known auto-injectors are cylindrical in shape and include vial containing a liquid medicament and a spring loaded needle to automatically penetrate the user's skin and inject the medicament. The storage of certain medicaments in a liquid form, however, can result in a shorter shelf life and/or an unstable medicament. Accordingly, some known auto-injectors include a vial containing a first medicament and a medicament stored separately. Such auto-injectors are often referred to as “wet/dry” auto-injectors, because one medicament is often a liquid (e.g., water) and the other medicament is often a solid (e.g., glucagon powder). In use, the first medicament and the second medicament must be mixed prior to injection.
Some known wet/dry auto-injectors, however, require that the user manually actuate a mixing mechanism that must be used prior to injection. Such configurations can, however, result in incomplete mixing and/or injection occurring without mixing. Moreover, such configurations can be complicated, making them difficult for a user to operate during an emergency situation.
Some known wet/dry auto-injectors employ a single mechanism to automatically mix and inject the medicaments contained therein. Because the mixing operation is not independent from the injection operation in such configurations, however, the medicament can be injected prior to the completion of the mixing operation and/or prior to the auto-injector being properly positioned for the injection operation.
Thus, a need exists for an auto-injector that can separately store two or more medicaments and that can automatically mix and inject the medicaments in two distinct operations.